Engine with radially arranged working cylinders and piston scavenging pumps



July 12, 1938. I. 2Elss| I 2,123,325 ENGINE WITH RADIALLY ARRANGED WORKING CYLINDERS AND PISTON SCAVENGING PUMPS,

Filed 001;. 21. 1956 2 Sheets-Shget 1 III/III July 12; 1938. Z L 2,123,325

ENGINE WITH RADIALLY ARRAIKIED WORKING CYLINDERS AND PISTON SCAVENGI NG PUMPS Filed Oct. 21, less 2 Sheets-Sheet 2 /n ventor: Z @5882 Patented July12,;1938

ENGINE WITH RADIALLY ARRANGED WORKING CYLINDERS AND PISTON SCAY- ENGING PUMPS Ignaz Zeissl, Vienna, Austria Application October 21, 1936, Serial No. 106,881 In Austria October 24, 1935 p 2 Claims.

The known constructions of controlling the suction ports of the piston-scavenging of two stroke engines possess such considerable drawbacks that the slight enlarging of these engine- 5 types is connected to a great extent with these drawbacks. In most of these engines, the suction ports of the scavenging pump are controlled by automatically operating flaps which, however, start to wobble at higher numbers of revolutions and do not operate satisfactory anymore. Compared with the four stroke engine, the advantages of simplicity are lost if valves or slides operated by control members are arranged, because in this event the construction of the engine becomes complicated. Finally engines are known, in which the suction ports of, the scavenging pumps are opened by the scavenging piston just before the latter reaches its dead centre, thus where the scavenging piston controls the suction ports. However in this construction, during the suetion stroke of the piston, a vacuum depending on the extent of the clearance is formed in the scavenging cylinder with the result of an unnecessary expenditure of power, hot scavenging air and thus small efllciency of the engine.

The present invention has for its object to obviate these drawbacks in the case of engines provided with two sets of radially arranged cylinders, one of said sets comprising solely working cylinders and the other set consists of corresponding scavenging cylinders only, and the essential feature of the present invention consists in that always one working cylinder and one scavenging cylinder are co-opcrating in such manner that the piston of the working cylinder controls the inlet and outlet of air into and out of the corresponding scavenging cylinder. Further according to the invention, the pistons of each set are mounted on separate cranks of a] crank-shalt, which are displaced with respect to one another in such manner, that the co-operating workingand scavenging cylinders may be arranged behind one another whereby, however, the scavenging cylinder is timely controlled by the piston of the working cylinder. This arrangement possesses the advantages of render ing unnecessary the provision of connecting flues or pipes between the two cylinders and further the scavenging cylinder is shielded by the working cylinder, whereby not only the weight but also the air-resistance of the engine are reduced;

these advantages being of particular importance in the construction of aircraft engines.

One mode of carrying out the present invention is illustrated by way of example and partly in section in the accompanying drawings.

Fig. 1 is a vertical section through the engine, with the working piston at top dead centre.

Fig. 2 is a diagram of the position of the cranks of the working piston I and scavenging piston II, corresponding to Fig. 1. v I

Fig. 3 is a section through the engine with the working-piston at bottom dead centre.

Fig. 4 shows the position of the cranks corresponding to Fig. 3.

In the drawing a is a cylinder of the working set, b its piston, e a cylinder of the scavenging set and 1 its piston. Both pistons operate'on separate cranks d, h of a crank-shaft through connecting rods 0, g. The crank h of the scavenging cylinder is in advance by approximately degrees. Further, k is the duct leading from the scavenging cylinder e to the working cylinder 0., m is the scaveng g port of the working cylinder and n the suction port ofthe latter. Air is sucked by way of the port 11. from the crank-case of the working set. '0 is the exhaust port.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is-- 1. An engine having a set oi. radially arranged working cylinders and a set of radially arranged scavenging cylinders each co-operating with one of the working cylinders, pistons reciprocating in' the cylinders, and a passage connecting each scavenging cylinder with the corresponding working cylinder, with one port in the scavenging cylinder and two piston-controlled ports in the combustion space of the cylinder and the other opens into the lower part of the cylinder below the piston.

2. An engine as claimed in claim 1, having each scavenging cylinder arranged beside the corresponding working cylinder, and having a crank shaft, with one crank for the pistons of all the working cylinders and another crank, displaced with respect to the first crank, for the pistons of all the scavenging cylinders.

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working cylinder, of which one opens into the 

